In general, a plurality of fluorescent lights are installed on a ceiling of an indoor parking lot. Fluorescent lights as light sources are relatively inexpensive but have a relatively short life span, and the brightness of the fluorescent lights decreases over time.
A radiation angle corresponding to an angle by which light is emitted is 120 degrees or more, and a parking lot is illuminated at intensities of illumination which are similar as a whole.
In order to solve a problem of a fluorescent light as a light source, which has a relatively short life span and a brightness of which gradually decreases over time, technologies for employing LEDs having a relatively long life span and consuming low electric power as lighting units of an indoor parking lot have been developed.
Korean Patent Application Publication No. 10-2010-0086709 discloses such an example. Korean Patent Application Publication No. 10-2010-0086709 discloses a lighting control device for a basement parking lot, for lighting an indoor parking lot using LEDs which are partially switched on according to a motion of a person.
However, although the device is designed to save electrical energy by simply replacing fluorescent lamps according to the related art by LED units, and selectively switching on and off the LED units according to a motion of a vehicle, it is further difficult to prevent crime and maintain security because there is no lighting unit around a hidden person who minimizes a motion.
Further, sensors for detecting a motion of a vehicle or a person should be installed at important points, and because a switching system for coping with detection results of the sensors should be equipped, installation costs increase and maintenance costs also increase.
In addition, in a lighting device of an indoor parking lot including a basement parking lot and an above-ground parking lot according to the related art, lighting units should be installed one the upper sides of a track of a vehicle and a parking space, energy consumption is relatively high.